大断面公路隧道的过程设计方法研究

 通过龙头山隧道、岚峰隧道的现场试验研究和数值分析，提出大断面公路隧道的过程设计方法，并建立应用模型。过程设计方法以荷载–结构法为基础，并以极限拉应变值来确定围岩松动区范围。与传统的公路隧道设计规范、普氏理论等方法相比，设计荷载中重点考虑施工过程的影响，从而在保证隧道安全性的同时优化偏于保守的支护参数。通过双侧壁导坑开挖方法和单侧壁导坑开挖方法这2个应用实例表明：过程设计方法比状态设计方法更为可靠和实用，更符合大断面隧道的实际情况。研究结果将有助于为大断面公路隧道寻求更为有效、合理的设计方法，提高大断面隧道的设计水平。

STUDY OF PROCESS DESIGN METHOD OF LARGE CROSS-SECTION ROAD TUNNEL

Process design method(PDM) of road tunnel with large cross-section is introduced according to the in-situ test study and finite element method(FEM) numerical simulation analysis of road tunnels in Longtoushan and Lanfeng，while the correlative practical mode is built subsequently. PDM is established based on the load-structure design method，and the loose load zone is defined by maximum tension strain of surrounding rock. PDM emphasizes more consideration about effect of a tunnel construction process，which is very different from both traditional road tunnel design codes and Протодъякнов?s(PUSI) theory. PDM optimizes the comparatively conservative support parameters by common design method，at the same time，of course can ensure the tunnel be at a whole safe state. Two engineering applications with different construction methods：double and single side-wall drift pilot excavations are studied，and the results show that PDM is more credible and practical than usual state one，and is better fit for the in-situ construction of tunnels with large cross-section. The results from this paper are in favor of advancing more efficient and reasonable design method of road tunnel with large cross-section，as well as to promote the current design level.